There are hints of an upcoming device in the firmware updates, but we don't know when they are going to be released nor what they're going to be. Since the hints are in the existing firmware, I wouldn't expect much of a difference on the software front and, as tshering noted, not much of a change in the screen.

If you think that the mini and Touch are a good deal at current prices, I'd go for it. I can't speak for the mini, but the Touch is a solid device.